Effects of cascade reservoirs in the Yangtze River Basin on estuarine saltwater intrusion and freshwater resources during late summer and early autumn

doi:10.3969/j.issn.1000-5641.2014.01.010

Abstract

Abstract:

Large cascade reservoirs in basins impound water in late summer and early autumn and release water in the dry season of the following year. These activities affect seasonal river discharge into the sea which, in turn, affects saltwater intrusion in estuaries and the utilization of freshwater resources. This study evaluated the effective storage capacity of large cascade reservoirs and the value of cross-basin water transfers by the South-to-North Water Transfer Project in the Yangtze River Basin. The estuarine and coastal three-dimensional numerical model ECOM-si was used to simulate and analyze the impact of major projects on estuarine saltwater intrusion and freshwater resources. In 2020, the effective storage capacity of large reservoirs built in the middle and upper reaches of the Yangtze River Basin was 70.611 billion cubic meters with a mean reduction in monthly river discharge of 13,398 m³/s during the storage period of September to October. By 2035, the completion of additional reservoirs in the basin will raise the total effective storage capacity of these reservoirs to 94.388 billion cubic meters and reduce the average monthly runoff by 17909 m³/s during the storage period. Using data on average monthly river discharge measured at the Datong Hydrological Station from 1950 to 2020, and by taking into account variations in river discharge by major projects in the basin, the average monthly river discharge from August to October from 2020 to 2035 in regular- and extra dry hydrological years was calculated. Numerical simulation results show that saltwater intrusion from September to October will increase due to impoundment in cascade reservoirs and decreased river discharge. During regular hydrological years, freshwater can be obtained from the four water reservoirs in the South Branch of the Yangtze River Estuary from September to October. However, water from the Dongfengxisha, Taicang, Chenhang, and Qingcaosha reservoirs is unsuitable for water intake during these months, particularly in extremely dry years. In 2020, the total number of consecutive days with unsuitable water intake from the four reservoirs was 28.75, 24.99, 29.63, and 37.47 days, respectively, and is predicted to rise to 46.53, 44.18, 47.56, and 50.75 days, respectively, in 2035. The impoundment of basin reservoirs in late summer and early autumn during average- and extremely dry hydrological years exposes them to strong northerly winds which can significantly decrease water intake. Basin reservoirs should reduce storage capacity and release water during extremely dry years to ensure the safety of freshwater resources in the Yangtze River Estuary.

Key words: basin reservoirs, river discharge, the Yangtze River Estuary, saltwater intrusion, numerical simulation

CLC Number:

P731.2

Zhi JIN, Jianrong ZHU, Wei QIU. Effects of cascade reservoirs in the Yangtze River Basin on estuarine saltwater intrusion and freshwater resources during late summer and early autumn[J]. Journal of East China Normal University(Natural Science), 2024, 2024(1): 90-103.

Figures/Tables 16

Fig.1

Fig.2

Table 1

Fig.3

Fig.4

Fig.5

Fig.6

Table 2

Fig.7

Table 3

Fig.8

Table 4

Fig.9

Fig.10

Fig.11

Fig.12

References 22

1	沈焕庭, 茅志昌, 朱建荣. 长江河口盐水入侵 [M]. 北京: 海洋出版社, 2003: 15-74.
2	罗小峰, 陈志昌.. 径流和潮汐对长江口盐水入侵影响数值模拟研究. 海岸工程, 2005, 24 (3): 1- 6.
3	WU H, ZHU J R, CHEN B R, et al.. Quantitative relationship of runoff and tide to saltwater spilling over from the North Branch in the Changjiang Estuary: A numerical study. Estuarine, Coastal and Shelf Science, 2006, 69 (1): 125- 132.
4	朱建荣, 吴辉, 李路, 等.. 极端干旱水文年(2006)中长江河口的盐水入侵. 华东师范大学学报 (自然科学版), 2010, (4): 1- 6.
5	李林江, 朱建荣.. 冬季北风风速对长江河口盐水入侵的影响. 海洋学报, 2021, 43, 10- 22.
6	LI L, ZHU J R, WU H.. Impacts of wind stress on saltwater intrusion in the Yangtze Estuary. Science China Earth Sciences, 2012, 55 (7): 1178- 1192.
7	ZHU J R, CHENG X Y, LI L J, et al.. Dynamic mechanism of an extremely severe saltwater intrusion in the Changjiang estuary in February 2014. Hydrology and Earth System Sciences, 2020, 24, 5043- 5056.
8	LI L, ZHU J R, WU H, et al.. Lateral saltwater intrusion in the North Channel of the Changjiang Estuary. Estuaries and Coasts, 2014, 37 (1): 36- 55.
9	鲍道阳, 朱建荣.. 近60年来长江河口河势变化及其对水动力和盐水入侵的影响Ⅲ: 盐水入侵. 海洋学报, 2017, 39, 1- 15.
10	CHEN Q, ZHU J R, LYU H H, et al.. Impacts of topography change on saltwater intrusion over the past decade in the Changjiang Estuary. Estuarine, Coastal and Shelf Science, 2019, 231, 1- 17.
11	李志鹏, 朱建荣.. 2007—2016年北支河势变化对长江口盐水入侵影响数值研究. 华东师范大学学报(自然科学版), 2022, (6): 109- 124.
12	ZHU J R, DING P X, ZHANG L Q, et al. Influence of the deep waterway project on the Changjiang Estuary [M]// WOLANSKI E. The Environment in Asia Pacific Harbours. Dordrecht, Netherlands: Springer, 2006: 79-92.
13	LYU H H, ZHU J R, CHEN Q, et al.. Impact of estuarine reclamation projects on saltwater intrusion and freshwater resource. Journal of Oceanology and Limnology, 2023, 41 (1): 38- 56.
14	QIU C, ZHU J R.. Influence of seasonal runoff regulation by the Three Gorges Reservoir on saltwater intrusion in the Changjiang River Estuary. Continental Shelf Research, 2013, 71, 16- 26.
15	AN Q, WU Y Q, TAYLOR S, et al.. Influence of the Three Gorges Project on saltwater intrusion in the Yangtze River Estuary. Environmental Geology, 2009, 56 (8): 1679- 1686.
16	张蔚, 郁夏琰, 徐怡, 等.. 三峡流量调节对长江口潮汐不对称的影响. 河海大学学报(自然科学版), 2020, 48, 143- 149.
17	丁磊, 缴健, 杨啸宇, 等.. 上游水库群运行对长江口淡水资源的影响及未来趋势分析. 海洋工程, 2022, 40, 130- 142.
18	雷静, 汪伟, 傅巧萍.. 长江水资源开发利用的径流累积影响研究: 以大通断面为例. 水利水电技术, 2021, 52, 25- 34.
19	仲志余, 邹强, 王学敏, 等.. 长江上游梯级水库群多目标联合调度技术研究. 人民长江, 2022, 53, 12- 20.
20	LYU H H, ZHU J R.. Impact of the bottom drag coefficient on saltwater intrusion in the extremely shallow estuary. Journal of Hydrology, 2018, 557, 838- 850.
21	海洋图集编委会. 渤海黄海东海海洋图集(水文) [Z]. 北京: 海洋出版社, 1992: 13-168.
22	ALLEN J I, SOMERFIELD P J, GILBERT F J.. Quantifying uncertainty in high-resolution coupled hydrodynamic-ecosystem models. Journal of Marine Systems, 2007, 64 (1): 3- 14.

水电站	河流	建成时间	有效库容/亿m³
乌江渡	乌江	1983年	13.50
宝珠寺	白龙江	1998年	13.40
二滩	雅砻江	2000年底	33.70
三峡	长江西陵峡	2003年	221.50
洪家渡	乌江	2004年7月	33.61
紫坪铺	岷江	2006年5月	7.74
彭水	乌江	2008年	5.18
构皮滩	乌江	2009年7月	31.54
瀑布沟	岷江	2010年12月	38.94
亭子口	嘉陵江	2014年5月	17.50
溪洛渡	金沙江下游	2014年6月	64.60
向家坝	金沙江下游	2014年7月	9.03
锦屏一级	雅砻江	2014年11月	49.10
观音岩	金沙江中游	2016年5月	5.55
乌东德	金沙江下游	2020年6月	30.00
岗托	金沙江上游	2020年7月	5.35
白鹤滩	金沙江下游	2022年	104.00
两河口	雅砻江	2023年	65.64
拉哇	金沙江上游	2024年2月	8.24
双江口	大渡河	2024年	19.17
叶巴滩	金沙江上游	2024年	5.37

参数	站位	CC	RMSE	SS
水位	堡镇水文站	0.96	0.26 m	0.98
	崇西水文站	0.96	0.26 m	0.98
	南门水文站	0.97	0.27 m	0.98
流速	1#浮标站	0.74/0.73/0.69	0.29/0.25/0.22 m/s	0.83/0.83/0.81
	2#浮标站	—	—	—
	3#浮标站	0.69/0.75/0.64	0.38/0.32/0.30 m/s	0.82/0.84/0.78
	4#浮标站	0.77/0.85/0.89	0.31/.018/0.09 m/s	0.81/0.88/0.94
	5#浮标站	0.91/0.89/0.77	0.28/0.29/0.27 m/s	0.93/0.92/0.88
	6#浮标站	0.87/0.87/0.86	0.30/0.26/0.21 m/s	0.92/0.93/0.92
盐度	1#浮标站	0.81	3.33	0.90
	2#浮标站	0.94	1.93	0.96
	3#浮标站	0.88	0.83	0.93
	4#浮标站	—	—	—
	5#浮标站	0.84	0.51	0.90
	6#浮标站	0.89	0.07	0.91

试验	8—10月各月径流量/(m³·s^–1)	风场	说明
Exp0	44392、43271、36332	多年10日平均	本底试验, 平均径流量, 不考虑流域工程对径流量调节
Exp1	43392、28873、21934	多年10日平均	基于Exp0, 考虑至2020年已建水库和南水北调工程
Exp2	42792、23762、16823	多年10日平均	基于Exp1, 考虑至2035年已建水库和南水北调工程
Exp3	42792、23762、16823	除了强风时段, 其余时间多年10日平均	基于Exp2, 考虑 9 月中下旬小潮期间3 d强北风, 风速12 m/s
Exp4	42792、23762、16823	除了强风时段, 其余时间多年10日平均	基于Exp2, 考虑 9 月中下旬小潮期间8 d强北风, 风速20 m/s
Exp5	42792、23762、16823	除了强风时段, 其余时间多年10日平均	基于Exp2, 考虑10月中下旬小潮期间3 d强北风, 风速12 m/s
Exp6	42792、23762、16823	除了强风时段, 其余时间多年10日平均	基于Exp2, 考虑10月中下旬小潮期间8 d强北风, 风速20 m/s
Exp7	27272、24967、20876	多年10日平均	本底试验, 特枯水文年, 不考虑流域工程对径流量调节
Exp8	26272、10569、6478	多年10日平均	基于Exp7, 考虑至2020年已建水库和南水北调工程
Exp9	25672、5458、1367	多年10日平均	基于Exp7, 考虑至2035年已建水库和南水北调工程

水库站点	不同数值试验下连续不可取水天数/d
水库站点	Exp0	Exp1	Exp2	Exp3	Exp4	Exp5	Exp6	Exp7	Exp8	Exp9
东风西沙	0	0	0	0	2.22	0	6.58	0	28.75	46.35
太仓	0	0	0	0	5.37	2.31	8.01	0	24.99	44.18
陈行	0	0	0	0	6.05	2.75	8.65	0	29.63	47.56
青草沙	0	0	0	5.48	11.64	7.28	11.4	0	37.47	50.75

[1]	CHEN Shi-qian, ZHU Jian-rong. Three-dimensional numerical simulation of the drift and diffusion of oil film at the highway bridge in the Yalu River [J]. Journal of East China Normal University(Natural Sc, 20120, 2012(6): 46-56.
[2]	GAO Qin-qin， ZHU Jian-rong， DUAN Yi-hong， SUN Ming-hua. Impacts of the symmetrical and unsymmetrical typhoons on the storm surge simulation in the East China and the South China Seas [J]. Journal of East China Normal University(Natural Sc, 20120, 2012(6): 57-72.
[3]	Jiaming CHEN, Shiming WANG, Rongrong YANG, Ziyan CHEN, Xia LIANG, Lijun HOU. Temperature adaptability of dark carbon fixation in seawater fromthe Yangtze River Estuary [J]. Journal of East China Normal University(Natural Science), 2024, 2024(1): 104-112.
[4]	Wei QIU, Jianrong ZHU. Responses of saltwater intrusion in the Changjiang Estuary to various river discharge under a persistent and strong northerly wind [J]. Journal of East China Normal University(Natural Science), 2023, 2023(3): 132-146.
[5]	Zhiyong YOU, Bolin LIU, Cheng LIU, Dengzhou GAO. Temperature sensitivity and controlling factors of nitrogen fixation processes in sediments of the Yangtze River Estuary [J]. Journal of East China Normal University(Natural Science), 2022, 2022(3): 101-108.
[6]	Zhipeng LI, Jianrong ZHU. Numerical simulation of the North Branch regime change impact on saltwater intrusion in the Yangtze River Estuary from 2007 to 2016 [J]. Journal of East China Normal University(Natural Science), 2022, 2022(3): 109-124.
[7]	Jinghua GU, Jianrong ZHU, Cheng QIU, Rui YUAN, Zhipeng LI, Wei QIU, Zhi JIN. Analysis of the long-term evolution of saltwater intrusion in the Changjiang Estuary [J]. Journal of East China Normal University(Natural Science), 2021, 2021(6): 174-186.
[8]	Yunping SONG, Jianrong ZHU. Numerical simulation and analysis of the spatial and temporal variations in residual water levels of the Changjiang Estuary [J]. Journal of East China Normal University(Natural Science), 2021, 2021(4): 121-133.
[9]	Yiping ZHU. Analysis of the characteristics of the Qingcaosha Reservoir direct saltwater intrusion from the open sea in the Changjiang Estuary [J]. Journal of East China Normal University(Natural Science), 2021, 2021(2): 21-29.
[10]	Zhengdong YANG, Jianrong ZHU, Yunping SONG, Jinghua GU. Spatial and temporal variations in the residual water level of the Changjiang Estuary and its cause [J]. Journal of East China Normal University(Natural Science), 2021, 2021(2): 12-20.
[11]	ZHU Jianrong, LU Peiyi, TANG Chuanmin, CHEN Qing, Lü Hanghang. Numerical simulation of saltwater intrusion mitigation by building a sluice in the North Branch of the Changjiang Estuary [J]. Journal of East China Normal University(Natural Science), 2020, 2020(3): 13-22.
[12]	TANG Chuanmin, ZHU Jianrong. Influence of water level rise on currents and saltwater intrusion in the Changjiang Estuary [J]. Journal of East China Normal University(Natural Science), 2020, 2020(3): 23-31.
[13]	SU Aiping, Lü Hanghang, WU Yufan. Impact of the South-to-North Water Diversion Project on saltwater intrusion and freshwater resources in the Changjiang Estuary [J]. Journal of East China Normal University(Natural Science), 2020, 2020(3): 32-42.
[14]	LU Peiyi, ZHU Jianrong, QIAN Weiwei, YUAN Lin. Numerical simulation of erosion and deposition at the water intake channel of the outer seawall sluice in the ecological restoration project area of Chongming Dongtan Bird Habitat [J]. Journal of East China Normal University(Natural Science), 2020, 2020(3): 43-54.
[15]	ZHU Ping, WU Hui. Water mass transport and its controlling mechanisms between the Changjiang Estuary and Subei Coastal Water during the summer [J]. Journal of East China Normal University(Natural Sc, 2018, 2018(4): 171-183.